A Novel Helical Superconducting Fault Current Limiter for Electric Propulsion Aircraft

It is crucial to achieve a high safety and reliability standard in future electric propulsion aircraft (EPA). Due to low short-circuit impedance and high rate of fault current rise in EPA systems, the superconducting fault current limiter (SFCL) plays a promising role, with advantages of lightweight, high efficiency, and compact size compared with conventional FCL. A novel helical bifilar coil is proposed, which is composed of two windings wound in opposite directions on the same bobbin; these are connected in series to achieve equal current sharing and a noninductive circuit. The 12-mm-wide stainless steel-reinforced superconducting tape from AMSC was used for the windings. To characterize the proposed helical bifilar coil connected in series (BCS), AC loss tests under three frequencies and quench tests under prospective fault current up to 2223 A were carried out. They were compared with the results measured from a conventional helical bifilar coil connected in parallel (BCP) that had an identical specification to the BCS. It was concluded that the AC losses measured in the BCP are dependent on the current and frequency. The fault current was suppressed effectively by the BCS at the first half peak from 2223 to 495 A, corresponding to 22.3% of the prospective fault current. The quench performance of BCP was also tested and discussed.